Bottle having a screw cap

ABSTRACT

A bottle ( 1 ) having a bottle main body ( 2 ) made from light metal and a neck ( 3 ) provided with an external thread ( 4 ), which bottle ( 1 ) comprises a capsule-type screw cap ( 5 ) with a cap ( 6 ) closing an opening of the bottle ( 1 ) and a skirt ( 7 ) adjoining the cap ( 6 ) and provided with a thread ( 8 ) co-operating with the external thread ( 4 ) of the neck ( 3 ), the edge ( 9 ) of the neck ( 3 ) of the bottle ( 1 ) being formed by an overturned portion ( 10 ) of the neck ( 3 ) forming a bead extending circumferentially around an opening of the bottle ( 1 ), and a free end of the over-turned portion ( 10 ) points in the direction of an external or internal face of the bottle ( 1 ), and the overturned portion ( 10 ) is of a curved design in the region of an apex ( 11 ) of the edge ( 9 ) facing the cap, and the edge ( 9 ) of the bottle ( 1 ) has an essentially O-shaped cross-section.

The invention relates to a bottle with a bottle main body made from light metal, a neck of the bottle having an external thread, and the bottle has a capsule-type screw cap with a cap closing an opening of the bottle and a skirt adjoining the cap, and the skirt has a thread co-operating with the external thread of the neck when the bottle is in the closed state.

Bottles of the type outlined above are often used as disposable bottles for drinks, in particular carbonated drinks. After filling and closing the bottles, high quality carbonated drinks may also be subjected to a pasteurization process. Due to the high temperatures and the carbon dioxide contained in the drinks, this can lead to a very high internal pressure in the bottle, for example 5-6 bar, which can undesirably result in carbon dioxide escaping in the region of the screw cap because sealing in the region of a closure of the bottle can become unsatisfactory due to the high internal pressure. However, reducing the carbon dioxide content results in an undesirable reduction in the quality of the drink.

It is therefore an objective of the invention to guarantee very good sealing of the bottle, even with a very high internal pressure in the bottle, and prevent carbon dioxide from escaping.

This objective is achieved on the basis of a bottle of the type outlined above due to the fact that the edge of the neck of the bottle is formed by an over-turned portion of the neck forming a bead extending circumferentially around an opening of the bottle main body, and a free end of the overturned portion points in the direction of and external or internal face of the bottle, and the overturned portion is of a curved design in the region of an apex of the edge facing the cap of the closure, and the edge of the bottle has an essentially O-shaped cross-section.

The solution proposed by the invention guarantees an optimum and tight abutment of the edge on the groove so that even when there is a high internal pressure in the bottle such as can occur during pasteurization, a strong seal tightness of the closure is obtained.

Due to the O-shaped cross-section of the edge, the overturned portion is closed as far as possible. In other words, a free end of the overturned portion either lies against the external surface of the bottle or a gap between the free end of the overturned portion and the external surface of the bottle is very small and is no more than 0.5 mm.

By particular preference, the screw cap has a main body made from a light metal. This embodiment is primarily distinctive due to the fact that the thread on the screw cap can be produced by means of one or more rollers, which emboss the external thread of the neck of the bottle in a blank of the screw cap during a rolling process.

Based on one advantageous variant of the invention which in addition to being lightweight also enables very slim wall thicknesses to be obtained, the bottle main body and/or the main body of the screw cap are made from aluminum or an aluminum alloy.

In a region between the neck and a base of the bottle, the main body of the bottle may have a wall thickness that is less than or equal to 0.5 mm.

To make it easy to open the bottle, an internal face of the skirt of the screw cap may be provided with a varnish and a coefficient of static friction between the varnish and aluminum is lower than a coefficient of static friction between aluminum and aluminum. The above-mentioned varnish may contain, for example, at least 1-2 parts by weight of a wax and/or other friction-reducing additives, for example graphite particles.

The opening process can by further simplified by coating an external face of the screw cap with a varnish and a coefficient of static friction between human skin and the matt varnish is greater than a coefficient of static friction between aluminum and human skin. The varnish used to coat the external face of the screw cap may contain friction-enhancing additives, for example rubber particles.

It has proved to be of particular advantage if the screw cap is closed with the exception of an opening for accommodating the neck of the bottle and the skirt of the screw cap has fluting comprising mutually spaced ribs in a portion disposed between the thread of the skirt and the cap, and the fluting has a depth of at least 0.1 mm. Opening the bottle is made much easier due to the depth of the fluting.

In the case of one very advantageous variant of the invention, the screw cap may have a tear-off ring which is connected to the skirt incorporating the thread by means of webs, and the neck of the bottle has a first support surface for a portion of the tear-off ring adjoining the external thread and disposed on the external face of the bottle, and the first support surface merges into a second support surface that is inclined relative to the first support surface and is likewise disposed on the external face of the bottle, and as viewed from the first support surface in the direction towards a base of the bottle, the second support surface is inclined in the direction towards a longitudinal mid-plane of the bottle, and an angle subtended by the first support surface and a portion of a plane extending at a tangent to the second support surface facing the first support surface is at most 45°.

The mechanical strength of the bottle is significantly higher than that of conventional bottles due to an angle of at least 45° in the region of the tear-off ring so that the bottle is not damaged by high pressures occurring in the interior of the bottle during pasteurization.

Easy opening of the bottle whilst simultaneously providing a strong seal tightness of the closure can be achieved if the external thread is a single-start thread and a value for a depth of the external thread lies in a range with a lower limit of 0.5 mm and an upper limit of 0.9 mm, and a value for a nominal diameter of the external thread lies in a range with a lower limit of 25 mm and an upper limit of 30 mm, a value for the height of the thread lies in a range with a lower limit of 9 mm and an upper limit of 15 mm, and the number of threads of the external thread is at least two, in particular between two and three. The high depth of the thread guarantees a good seal of the bottle whilst its relatively flat contour means that the screw cap can be turned with a small amount of force.

A small amount of force for turning the screw cap can be achieved if the external thread is a round thread and a value for a radius of curvature of a thread flank is selected from a range of between 0.4 and 0.8 mm.

The amount of force needed to open the bottle can be further reduced if at least the external thread is coated with a varnish, and a coefficient of static friction between the varnish and aluminum is lower than a coefficient of static friction between aluminum and aluminum.

Based on a preferred embodiment, the cap of the screw cap may have a sealing liner. The seal tightness of the bottle can be further increased due to the sealing liner, which is preferably made from plastic and can be injected into the screw cap for example.

To provide a clearer understanding, the invention will be described in more detail with reference to the appended drawings.

These are highly simplified, schematic diagrams illustrating the following:

FIG. 1 a section through a bottle proposed by the invention with the screw cap removed;

FIG. 2 a perspective view of a screw cap for the bottle illustrated in FIG. 1;

FIG. 3 a perspective view of a screw cap in an unfinished state;

FIG. 4 a contour of a neck of the bottle illustrated in FIG. 1 in more detail.

Firstly, it should be pointed out that the same parts described in the different embodiments are denoted by the same reference numbers and the same component names and the disclosures made throughout the description can be transposed in terms of meaning to same parts bearing the same reference numbers or same component names. Furthermore, the positions chosen for the purposes of the description, such as top, bottom, side, etc., relate to the drawing specifically being described and can be transposed in terms of meaning to a new position when another position is being described.

All the figures relating to ranges of values in the description should be construed as meaning that they include any and all part-ranges, in which case, for example, the range of 1 to 10 should be understood as including all part-ranges starting from the lower limit of 1 to the upper limit of 10, i.e. all part-ranges starting with a lower limit of 1 or more and ending with an upper limit of 10 or less, e.g. 1 to 1.7, or 3.2 to 8.1 or 5.5 to 10.

At this point, it should be noted that the following description relates to the drawings jointly.

As illustrated in FIG. 1, a bottle 1 proposed by the invention comprises a bottle main body 2 made from light metal, in particular aluminum or an aluminum alloy. The external and/or internal face of the bottle main body 2 may be totally or partially coated, for example varnished. The bottle main body 2 further comprises a neck 3 on which an external thread 4 is provided.

The external thread 4 is preferably a single-start thread. A depth of the external thread 4 advantageously lies between 0.5 mm and 0.9 mm. A nominal diameter of the external thread may be between 25 mm and 30 mm, for example. Based on the embodiment illustrated, the thread may have a height between limits of 9 mm and 15 mm. A number of threads of the external thread 4 is at least two, in particular between two and three. Particularly preferably, the number of threads of the external thread 4 is selected from a range of 2.2-2.5. The external thread 4 may be a round thread, in which case a radius of curvature of a thread flank is expediently between 0.4 and 0.8 mm.

The external thread 4 may be coated with a friction-minimizing varnish and a coefficient of static friction between the varnish and aluminum is lower than a coefficient of static friction between aluminum and aluminum.

The bottle 1 also comprises a capsule-type screw cap 5 illustrated in more detail in FIGS. 2 and 3. The screw cap 5 comprises a cap 6 and a skirt 7 into which a thread 8 corresponding to the external thread 4 is embossed so that the screw cap 5 can be released from the neck 3 by turning it and screwed back on to obtain closure. FIG. 3 illustrates the screw cap 5 in an unfinished state. In order to close the bottle 1 after filling it, the screw cap 5 illustrated in FIG. 3 is placed on the bottle 1 so that the skirt 7 lies over the external thread 4 of the neck 3 of the bottle. The contour of the external thread 4 is then embossed into the skirt 7 in a manner known per se by means of tools such as rollers, for example, although these are not illustrated. The screw cap 5 is thus connected to the bottle 1. The bottle 1 can then be opened by turning the screw cap 5 and can be closed again.

In order to minimize friction, an internal face of the skirt 7 of the screw cap 5 may be coated with a varnish and a coefficient of static friction between the varnish and aluminum is lower than a coefficient of static friction between aluminum and aluminum.

Naturally, both the internal face of the screw cap 5 and the external thread 4 may be varnished. In this case, it is of advantage if a coefficient of static friction between the two varnishes is lower than a coefficient of static friction between aluminum and aluminum.

In order to improve handling and make it easier to open the bottle 1, an external face of the screw cap 5 may also be coated with a varnish and a coefficient of static friction between human skin and the matt varnish is greater than a coefficient of static friction between aluminum and human skin. The varnish used for the external face of the screw cap 5 may be a so-called soft-touch varnish, for example.

At this stage, it should be pointed out that the specifications given in this document for coefficient of static friction relative to a coefficient of static friction between aluminum and aluminum should be understood as being a general reference in the sense of a quantitative value which does not depend on whether the material used for the bottle 1 or screw cap 5 is a different light metal. In other words, coefficient of static friction between aluminum and aluminum in this context is intended to mean a value of 1.05.

With the exception of an opening for accommodating the neck 3 of the bottle 1, the screw cap 5 may be of a closed design. In a portion disposed between the thread 8 of the skirt 7 and the cap 6, fluting 16 comprising mutually spaced ribs may be provided. The fluting 16 has a depth of at least 0.1 mm.

As may be seen from FIG. 3, the cap 6 may have a groove 18 with a U-shaped cross-section. The groove 18 may extend along an intrinsically closed curve, in particular along a circle, and may be disposed, for example, in a sealing liner 16 which is made from plastic and can be injected into the screw cap 5, for example. However, the groove 18 is not absolutely necessary and the groove 18 could also be dispensed with, for example, in which case the sealing liner 16 may also not have a groove 18 at all.

The edge 9 of the neck 3 of the bottle 1 is formed by an overturned portion 10 of the neck 3 having the shape of a bead extending circumferentially around an opening of the bottle main body 2. As may be seen from the diagram in in FIG. 1, edge 9 of the bottle 1 may have an essentially O-shaped cross-section. A free end of the overturned portion 10 may point in the direction towards an external surface of the bottle 1. In principle, however, it would be possible for the edge 9 to be turned inwards. In this case, the free end of the overturned portion 10 would be directed towards an internal surface of the bottle 1. In the region of an apex 11 facing the cap 6, the edge 9 is of a curved design.

As may be seen from FIG. 3, the screw cap 5 may have a tear-off ring 12 which is connected to the skirt 7 by means of webs 19. At the same time, as illustrated in FIGS. 1 and 4, the neck 3 of the bottle 1 may have a first support surface 13 for a portion of the tear-off ring 12 adjoining the external thread 4 and disposed on the external face of the bottle 1. The first support surface 13 merges into a second support surface 14 likewise disposed on the external face of the bottle 1. The second support surface 14 is inclined relative to the first support surface 13. As viewed in the direction from the first support surface 13, the second support surface 14 is inclined in the direction towards a longitudinal mid-plane e of the bottle 1. As illustrated in FIG. 4, an angle α subtended by the first support surface 13 and a portion of a plane t facing the first support surface 13 extending at a tangent to the second support surface 14 is at most 45°.

For the sake of good order, finally, it should be pointed out that in order to provide a clearer understanding of the structure of the bottle proposed by the invention, it and its constituent parts are illustrated to a certain extent out of scale and/or on a larger scale and/or on a smaller scale.

LIST OF REFERENCE NUMBERS

1 Bottle

2 Bottle body

3 Neck

4 External thread

5 Screw cap

6 Cap

7 Lateral surface

8 Thread

9 Edge

10 Portion

11 Apex

12 Tear-off ring

13 Support surface

14 Support surface

15 Sealing liner

16 Fluting

17 Webs

18 Groove

e Longitudinal mid-plane

t Tangential plane

α Angle 

1. Bottle (1) having a bottle main body (2) made from light metal and a neck (3) provided with an external thread (4), which bottle (1) comprises a capsule-type screw cap (5) with a cap (6) closing an opening of the bottle (1) and a skirt (7) adjoining the cap (6) having a thread (8) co-operating with the external thread (4) of the neck (3) when the bottle is in a closed state, wherein the edge (9) of the neck (3) of the bottle (1) is formed by an overturned portion (10) of the neck (3) forming a bead extending circumferentially around an opening of the bottle main body (2), and a free end of the overturned portion (10) points in the direction towards an external or internal face of the bottle (1), and the overturned portion (10) is of a curved design in the region of an apex (11) of the edge (9) facing the cap (6), and the edge (9) of the bottle (1) has an essentially O-shaped cross-section.
 2. Bottle according to claim 1, wherein the screw cap (5) comprises a main body (12) made from a light metal.
 3. Bottle according to claim 2, wherein the bottle main body (2) and/or the main body (12) of the screw cap (5) are made from aluminum or an aluminum alloy.
 4. Bottle according to claim 1, wherein an internal face of the skirt (7) of the screw cap (5) is coated with a varnish and a coefficient of static friction between the varnish and aluminum is lower than a coefficient of static friction between aluminum and aluminum.
 5. Bottle according to claim 1, wherein an external face of the screw cap (5) is coated with a varnish and a coefficient of static friction between human skin and the matt varnish is greater than a coefficient of static friction between aluminum and human skin.
 6. Bottle according to claim 1, wherein the screw cap (5) is closed with the exception of an opening for accommodating the neck (3) of the bottle (1) and the skirt (7) of the screw cap (5) has fluting (16) comprising mutually spaced ribs in a portion disposed between the thread (8) of the skirt (7) and the (6), and the fluting has a depth of at least 0.1 mm.
 7. Bottle according to claim 1, wherein the screw cap (5) has a tear-off ring (12) which is connected to the skirt (7) incorporating the thread (8) by means of webs (19), and the neck (3) of the bottle (1) has a first support surface (13) for a portion of the tear-off ring (12) adjoining the external thread (4) and disposed on the external face of the bottle (1), and the first support surface (13) merges into a second support surface (14) that is inclined relative to the first support surface (13) and likewise disposed on the external face of the bottle, and as viewed from the first support surface (13) in the direction towards a base of the bottle (1), the second support surface is inclined in the direction of a longitudinal mid-plane (e) of the bottle (1), and an angle (α), subtended by the first support surface (13) and a portion of a plane (t) extending at a tangent to the second support surface (14) facing the first support surface (13) is at most 45°.
 8. Bottle according to claim 1, wherein the external thread (4) is a single-start thread and a value for a depth of the external thread (4) lies in a range with a lower limit of 0.5 mm and an upper limit of 0.9 mm, and a value for a nominal diameter of the external thread (4) lies in a range with a lower limit of 25 mm and an upper limit of 30 mm, and a value for the height of the thread lies in a range with a lower limit of 9 mm and an upper limit of 15 mm, and a number of threads of the external thread (4) is at least two, in particular between two and three.
 9. Bottle according to claim 1, wherein the external thread (4) is a round thread and a value for a radius of curvature of a thread flank is selected from a range of between 0.4 and 0.8 mm.
 10. Bottle according to claim 1, wherein at least the external thread (4) is coated with a varnish and a coefficient of static friction between the varnish and aluminum is lower than a coefficient of static friction between aluminum and aluminum.
 11. Bottle according to claim 1, wherein the cap (6) of the screw cap (5) has a sealing liner (16).
 12. Bottle according to claim 11, wherein the sealing liner (16) is made from plastic. 